Talk to an Intellectual Property Lawyer

Patent protection doesn’t last forever. Indeed, patents are typically
the shortest lived of all forms of intellectual property protection.
When a patent expires, the invention described by the patent falls into
the public domain: it can be used by anyone without permission from the
owner of the expired patent. The basic technologies underlying
television and personal computers are good examples of valuable
inventions that are no longer covered by in-force patents.

How long a patent lasts depends on when the application was filed with the U.S. Patent and Trademark Office.

Patents Filed Through June 17, 1995

For U.S. patents filed through June 17, 1995, the patent lasts for 17
years from the date the patent is issued, provided that the fees
necessary to keep the patent in force (maintenance fees) are paid.

Patents Filed After June 17, 1995

For patent applications filed after June 17, 1995, the patent last 20
years from the date of filing. Since applications typically take one to
three years to process, most patents filed after 1995 have an effective
duration of 17-19 years.

Design Patents

Design patents, which protect only the ornamental appearance of an article, last for fourteen years from the issue date.

Patent Extensions

In some cases patents can be extended for up to five years. Examples
include where there have been delays in issuing the patent due to
interference proceedings, appellate review of the patent’s validity, or
failure of the U.S. Patent and Trademark Office to issue the patent
within three years.

New Developments May be Patentable

The fact that an invention is in the public domain does not mean that
subsequent developments based on the original invention are also in the
public domain. Rather, new inventions that improve public domain
technology are constantly being conceived and patented. For instance,
televisions and personal computers that roll off today’s assembly lines
employ many recent inventions that are covered by in-force patents.